1. Field of the Invention
The present invention relates to a camera capable of a focusing adjustment by a contrast method using an imaging signal output by an imaging element.
2. Description of Related Art
In this field of the art, as one of ways of automatic focus (AF) adjustments for use in a camera, there is a so-called contrast method. According to this method, an object is picked up by an imaging element such as CCD or so and an in-focus position is determined by using an imaging signal in a focus area. More specifically, a component of a given spatial frequency band of an imaging signal in a focus area is extracted through a band pass filter (BPF). By integration of these absolute values in an area, a focus evaluation value in causing a focusing operation is calculated. This focus evaluation value represents a contrast size, high or low and a peak of focus evaluation value shows a highest contrast. Namely, a peak value position turns out to be an in-focus position.
As a way of detecting a peak value position, what is called a mountain climb control method and a full scan control method are known. A single AF mode in which an automatic focusing is performed only when a halfway-depress switch is halfway depressed and a focus point is held unless a halfway-depressed switch is released and a continuous AF mode in which an automatic focusing operation is always being performed continuously regardless of an operation of a halfway-depress switch are known.
In a continuous AF mode, it is pointed out that when a halfway-depress switch is turned on, a suitable focusing control method is not always selected. It is an object of this invention to provide a camera enabling to select a suitable focusing control method when a halfway-depress switch is turned on.
In order to achieve the object, according to one aspect of this invention, there is provided a camera which includes an imaging element that picks up an image of an object through a taking-lens, an evaluation value calculator that calculates focus evaluation value based upon an imaging signal output by the imaging element, a selector that selects one focusing mode from a plurality of focusing modes, a focusing device that performs a focusing operation of the taking-lens based upon the focus evaluation value and the selected focusing mode and a rebooting device that reboots the focusing operation after the focusing operation performed by the focusing device finishes, an evaluation value memory device that obtains and stores a plurality of focus evaluation values calculated in time sequence by the evaluation value calculator after the focusing operation performed by the focusing device finishes and a fluctuation evaluator that evaluates fluctuation in focus evaluation value based upon a plurality of focus evaluation values stored into the evaluation value memory device, wherein, when the rebooting device reboots the focusing operation, the selector selects one focusing mode from a plurality of focusing modes based upon an evaluation result of fluctuation in focus evaluation value by the fluctuation evaluator.
According to claim 2 set forth in this invention, there is provided the camera disclosed in claim 1, wherein a plurality of focusing modes have a mountain climb focus mode using a so-called mountain climb control method that seeks a peak value of the focus evaluation value while moving the taking-lens in a direction with the focus evaluation value getting larger every a single cycle of calculating the focus evaluation value and a full range scan focus mode using a so-called full range scanning control method that seeks a peak value of the focus evaluation value by scanning across an overall movement range for use in focusing the taking-lens.
According to claim 3 set forth in this invention, there is provided the camera disclosed in claim 2, wherein the selector selects the mountain climb focus mode when the fluctuation evaluator judges that fluctuation in focus evaluation value is monotonous.
According to claim 4 set forth in this invention, there is provided the camera disclosed in claim 3, wherein a monotonous fluctuation in focus evaluation value means a monotonous increase or decrease in focus evaluation value within a given period of time.
According to claim 5 set forth in this invention, there is provided the camera disclosed in claim 2, wherein the selector selects the full range scan control mode when the fluctuation evaluator judges that fluctuation in focus evaluation value is not monotonous.
According to claim 6 set forth in this invention, there is provided the camera disclosed in claim 2, wherein the selector moves the taking-lens to an end of the movement range and selects the mountain climb focus mode when the fluctuation evaluator judges that fluctuation in focus evaluation value is not monotonous.
According to claim 7 set forth in this invention, there is provided the camera disclosed in claim 6, wherein the end of the movement range is an end at a closest distance away.
According to claim 8 set forth in this invention, there is provided a camera which includes an imaging element that picks up an image of an object through a taking-lens, an evaluation value calculator that calculates focus evaluation value based upon an imaging signal output by the imaging element, a selector that selects one focusing mode from a plurality of focusing modes, a focusing device that performs a focusing operation of the taking-lens based upon the focus evaluation value and the selected focusing mode and a rebooting device that reboots the focusing operation after the focusing operation performed by the focusing device finishes, wherein further comprising a plurality of focusing modes that have a mountain climb focus mode using a so-called mountain climb control method that seeks a peak value of the focus evaluation value while moving the taking-lens in a direction with the focus evaluation value getting larger every a single cycle of calculating the focus evaluation value and a full range scan focus mode using a so-called a full range scanning focus control method that seeks a peak value of focus evaluation value by scanning across an overall movement range for use in focusing the taking-lens, wherein, when the rebooting device reboots the focusing operation, the selector selects the full range scan focus mode when the selector judges that focus evaluation value at rebooting is smaller than a given value.
According to claim 9 set forth in this invention, there is provided the camera disclosed in claim 8, wherein the given value is a value calculated based upon focus evaluation value at a conclusion of the focusing operation.
According to claim 10 set forth in this invention, there is provided a camera which includes an imaging element that picks up an image of an object through a taking-lens, an evaluation value calculator that calculates focus evaluation value based upon an imaging signal output by the imaging element, a selector that selects one focusing mode from a plurality of focusing modes, a focusing device that performs a focusing operation of the taking-lens based upon the focus evaluation value and the selected focusing mode and a rebooting device that reboots the focusing operation after the focusing performed by the focusing device finishes, wherein, when the rebooting device reboots the focusing operation, the selector selects one focusing mode based upon a shooting condition.
According to claim 11 set forth in this invention, there is provided the camera disclosed in claim 10, wherein the shooting condition is a condition based upon a focal length of the taking-lens.
According to claim 12 set forth in this invention, there is provided the camera disclosed in claim 11, wherein a plurality of focusing modes have a mountain climb focus mode using a so-called mountain climb control method that seeks a peak value of the focus evaluation value while moving the taking-lens in a direction with the focus evaluation value getting larger every a single cycle of calculating the focus evaluation value and a full range scan focus mode using a so-called a full range scanning focus control method that seeks a peak value of focus evaluation value by scanning across an overall movement range for use in focusing the taking-lens and the selector selects the full range scan focus mode when the selector judges that the focal length is shorter than a given length.
According to claim 13 set forth in this invention, there is provided the camera disclosed in claim 10, wherein the shooting condition is a condition based upon a plurality of shooting modes predetermining a plurality of shooting conditions in accordance with a shooting situation.
According to claim 14 set forth in this invention, there is provided the camera disclosed in claim 13, wherein a plurality of focusing modes have a mountain climb focus mode using a so-called mountain climb control method that seeks a peak value of the focus evaluation value while moving the taking-lens in a direction with the focus evaluation value getting larger every a single cycle of calculating the focus evaluation value and a full range scan focus mode using a so-called a full range scanning focus control method that seeks a peak value of focus evaluation value by scanning across an overall movement range for use in focusing the taking-lens.
According to claim 15 set forth in claim 14, there is provided the camera disclosed in claim 13, wherein the selector selects the mountain climb focus mode when the shooting mode is any of a portrait, a close-up or a sport shooting mode.
According to claim 16 set forth in this invention, there is provided the camera disclosed in claim 14, wherein the selector selects the full range scan focus mode when the shooting mode is any of a long distance or a night scenery shooting mode.
According to claim 17 set forth in this invention, there is provided a camera which includes an imaging element that picks up an image of an object through a taking-lens, an evaluation value calculator that calculates focus evaluation value based upon an imaging signal output by the imaging element, a selector that selects one focusing mode from a plurality of focusing modes, a focusing device that performs a focusing operation of the taking-lens based upon the focus evaluation value and the selected focusing mode and a rebooting device that reboots the focusing operation after the focusing operation performed by the focusing device finishes, wherein the plurality of focusing modes include a full range scan focus mode using a so-called full scanning control method that seeks a peak value of the focus evaluation value by scanning across an overall range for use in focusing the taking-lens and at rebooting the focusing operation by the rebooting device, the selector selects the full range scan focus mode when amount of fluctuation in the focus evaluation value at rebooting with reference to the focus evaluation value at concluding the focusing operation is larger than a given value.
According to claim 18 set forth in this invention, there is provided the camera disclosed in claim 17, wherein the given value is a value obtained based upon focus evaluation value at concluding the focusing operation.
According to claim 19 set forth in this invention, there is provided the camera disclosed in claim 17, wherein the plurality of focusing modes include a mountain climb focus mode using a so-called mountain climb control method that seeks a peak value of the focus evaluation value while moving the taking-lens in a direction with the focus evaluation value getting larger every a single cycle of calculating the focus evaluation value.
According to claim 20 set forth in this invention, there is provided a camera which includes an imaging element that picks up an image of an object through a taking-lens, an evaluation value calculator that calculates focus evaluation value based upon an imaging signal output by the imaging element, a selector that selects one focusing mode from a plurality of focusing modes including a focusing mode using a so-called full scanning control method that seeks a peak value of the focus evaluation value by scanning across an overall range for use in focusing the taking-lens, a focusing device that performs a focusing operation of the taking-lens based upon the focus evaluation value and the selected focusing mode, an AF selector that selects a so-called continuous AF mode continuously repeating the focusing operation by the focusing device and a rebooting device that reboots the focusing operation after the focusing operation performed by the focusing device finishes, wherein,
when the focusing device is disable to perform the focusing operation in the continuous AF mode selected by the AF selector, a selector selects a focusing mode using a full range scanning control method when a focusing operation is rebooted by the rebooting device.
According to claim 21 set forth in this invention, there is provided a camera which includes an imaging element that picks up an image of an object through a taking-lens, an evaluation value calculator that calculates focus evaluation value based upon an imaging signal output by the imaging element, a focus instruction switch that instructs a focusing operation when a switch is turned on, a selector that selects at least one focusing mode from any of a first focusing mode or a second focusing mode based upon the focus evaluation value when the focus instruction switch is turned on and a focusing device that performs a focusing operation of the taking-lens based upon the focus evaluation value and the selected one focusing mode when the focus instruction switch is turned on.
According to claim 22 set forth in this invention, there is provided the camera disclosed in claim 21, wherein the first focusing mode is a so-called mountain climb control method that seeks a peak value of the focus evaluation value while moving the taking-lens in a direction with the focus evaluation value getting larger every a single cycle of calculating the focus evaluation value and the second focusing mode is a so-called a full range scanning focus control method that seeks a peak value of focus evaluation value by scanning across an overall movement range for use in focusing the taking-lens.
According to claim 23 set forth in this invention, there is provided the camera disclosed in claim 22, wherein, when the focus evaluation value at a time of the focus instruction switch being turned on is larger than a given value, the selector selects the mountain climb control method.
According to claim 24 set forth in this invention, there is provided the camera disclosed in claim 22, wherein, when the focus evaluation value at a time of the focus instruction switch being turned on is smaller than a given value, the selector selects the full range scanning focus control method.
According to claim 25 set forth in this invention, there is provided a camera which includes an imaging element that picks up an image of an object through a taking-lens, an evaluation value calculator that calculates focus evaluation value based upon an imaging signal output by the imaging element, a selector that selects at least one focusing mode from any of a first focusing mode or a second focusing mode, a focusing device that performs a focusing operation of the taking-lens based upon the focus evaluation value and the selected one focusing mode, an evaluation memory device that stores the focus evaluation value when a focusing operation finishes, a re-focus instruction switch that instructs again the focusing device to perform a focusing operation when a switch is turned on and an evaluation value comparison device that obtains amount of fluctuation in the focus evaluation value at a time of there-focus instruction switch being turned on with reference to the focus evaluation value stored by the evaluation value memory device, wherein, when the re-focus instruction switch is turned on, the selector selects the one focusing mode based upon the amount of fluctuation obtained by the evaluation value comparison device.
According to claim 26 set forth in this invention, there is provided the camera disclosed in claim 25, wherein the first focusing mode is a so-called mountain climb control method that seeks a peak value of the focus evaluation value while moving the taking-lens in a direction with the focus evaluation value getting larger every a single cycle of calculating the focus evaluation value and the second focusing mode is a so-called a full range scanning focus control method that seeks a peak value of focus evaluation value by scanning across an overall movement range for use in focusing the taking-lens.
According to claim 27 set forth in this invention, there is provided the camera disclosed in claim 26, wherein, when the amount of fluctuation is smaller than a given value, the selector selects the mountain climb control method.
According to claim 28 set forth in this invention, there is provided the camera disclosed in claim 27, wherein the given value is a value obtained based upon the focus evaluation value stored into the evaluation value memory device.
According to claim 29 set forth in this invention, there is provided the camera disclosed in claim 26, wherein, when the amount of fluctuation is larger than a given value, the selector selects the full range scanning focus control method.
According to claim 30 set forth in this invention, there is provided a camera which includes an imaging element that picks up an image of an object through a taking-lens, an evaluation value calculator that calculates focus evaluation value based upon an imaging signal output by the imaging element, a selector that selects one focusing mode from a plurality of focusing modes including a focusing mode using a so-called full range scanning focus control method that seeks a peak value of focus evaluation value by scanning across an overall movement range for use in focusing the taking-lens, a focusing device that performs a focusing operation of the taking-lens based upon the focus evaluation value and the selected focusing mode, an AF selector that selects a so-called continuous AF mode continuously repeating the focusing operation by the focusing device and a focus instruction switch that instructs the focusing device to perform a focusing operation when a switch is turned on, wherein, when the focusing device is disable to perform the focusing operation in the continuous AF mode selected by the AF selector, the selector selects a focusing mode using the full range scanning control method at a time the focus instruction switch is turned on.
According to claim 31 set forth in this invention, there is provided the camera disclosed in claim 30, wherein the plurality of focusing modes include a focusing mode using a so-called mountain climb control method that seeks a peak value of the focus evaluation value while moving the taking-lens in a direction with the focus evaluation value getting larger every a single cycle of calculating the focus evaluation value.